This invention relates to a program counter display device for displaying the contents of a program counter.
Generally, in debugging a computer program, the operation stage of the program is traced, to recognize the operation thereof. The operation stage of the program can be known from the contents (memory addresses) of a program counter. However, the memory addresses represented by binary numbers or hexadecimal numbers are difficult to correlate with the actual program lines (statements) of a program written in high-level language, and too difficult to handle. The actual program can be executed, but the statement number of a statement being executed and the program list cannot be displayed simultaneously. It is thus difficult to correlate a statement number with a program statement. Since the statement number is displayed as numeric data, it is difficult to trace the numeric data in order to monitor the execution state of the program.
A program generally possesses a control structure such as repetitions(loops), and elements for changing the program flow, such as branches, subroutine read-out, etc. Therefore, in debugging the program, the ability to recognize the control structure of the program and the program flow therein is desirable. However, it has hitherto been difficult to recognize the control structure and the program flow, since in the prior art, only the contents of a program counter or the statement numbers of the debug program are displayed.